著者

Arisa Nishihara Shin Haruta Shawn E. McGlynn Vera Thiel Katsumi Matsuura

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17134, (Released:2018-01-24)

被引用文献数

21

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The activity of nitrogen fixation measured by acetylene reduction was examined in chemosynthetic microbial mats at 72–75°C in slightly-alkaline sulfidic hot springs in Nakabusa, Japan. Nitrogenase activity markedly varied from sampling to sampling. Nitrogenase activity did not correlate with methane production, but was detected in samples showing methane production levels less than the maximum amount, indicating a possible redox dependency of nitrogenase activity. Nitrogenase activity was not affected by 2-bromo-ethane sulfonate, an inhibitor of methanogenesis. However, it was inhibited by the addition of molybdate, an inhibitor of sulfate reduction and sulfur disproportionation, suggesting the involvement of sulfate-reducing or sulfur-disproportionating organisms. Nitrogenase activity was affected by different O2 concentrations in the gas phase, again supporting the hypothesis of a redox potential dependency, and was decreased by the dispersion of mats with a homogenizer. The loss of activity that occurred from dispersion was partially recovered by the addition of H2, sulfate, and carbon dioxide. These results suggested that the observed activity of nitrogen fixation was related to chemoautotrophic sulfate reducers, and fixation may be active in a limited range of ambient redox potential. Since thermophilic chemosynthetic communities may resemble ancient microbial communities before the appearance of photosynthesis, the present results may be useful when considering the ancient nitrogen cycle on earth.

著者

ザヴァルジン ゲア 石本 真

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Bulletin of Japanese Society of Microbial Ecology(日本微生物生態学会報) (ISSN:09117830)

巻号頁・発行日

vol.6, no.1, pp.45-54, 1991-05-01 (Released:2009-10-05)

参考文献数

6

著者

平石 明

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Bulletin of Japanese Society of Microbial Ecology(日本微生物生態学会報) (ISSN:09117830)

巻号頁・発行日

vol.10, no.1, pp.31-42, 1995-05-31 (Released:2009-10-05)

参考文献数

38

被引用文献数

9 7

著者

Elhussein F Mourad Mohamed S Sarhan Hassan-Sibroe A Daanaa Mennatullah Abdou Ahmed T Morsi Mohamed R Abdelfadeel Hend Elsawey Rahma Nemr Mahmoud El-Tahan Mervat A Hamza Mohamed Abbas Hanan H Youssef Abdelhadi A Abdelhadi Wafaa M Amer Mohamed Fayez Silke Ruppel Nabil A Hegazi

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17135, (Released:2018-02-23)

被引用文献数

22

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In order to improve the culturability and biomass production of rhizobacteria, we previously introduced plant-only-based culture media. We herein attempted to widen the scope of plant materials suitable for the preparation of plant-only-based culture media. We chemically analyzed the refuse of turfgrass, cactus, and clover. They were sufficiently rich to support good in vitro growth by rhizobacteria isolates representing Proteobacteria and Firmicutes. They were also adequate and efficient to produce a cell biomass in liquid batch cultures. These culture media were as sufficient as artificial culture media for the cultivation and recovery of the in situ rhizobacteria of barley (Hordeum murinum L.). Based on culture-dependent (CFU plate counting) and culture-independent analyses (qPCR), mowed turfgrass, in particular, supported the highest culturable population of barley endophytes, representing >16% of the total bacterial number quantified with qPCR. This accurately reflected the endophytic community composition, in terms of diversity indices (S’, H’, and D’) based on PCR-DGGE, and clustered the plant culture media together with the qPCR root populations away from the artificial culture media. Despite the promiscuous nature of the plant materials tested to culture the plant microbiome, our results indicated that plant materials of a homologous nature to the tested host plant, at least at the family level, and/or of the same environment were more likely to be selected. Plant-only-based culture media require further refinements in order to provide selectivity for the in vitro growth of members of the plant microbiome, particularly difficult-to-culture bacteria. This will provide insights into their hidden roles in the environment and support future culturomic studies.

著者

Shingo Kato Sanae Sakai Miho Hirai Eiji Tasumi Manabu Nishizawa Katsuhiko Suzuki Ken Takai

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17165, (Released:2018-02-16)

被引用文献数

31

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Many thermophiles thriving in a natural high-temperature environment remain uncultivated, and their ecophysiological functions in the biogeochemical cycle remain unclear. In the present study, we performed long-term continuous cultivation at 65°C and 70°C using a microbial mat sample, collected from a subsurface geothermal stream, as the inoculum, and reconstructed the whole genome of the maintained populations using metagenomics. Some metagenome-assembled genomes (MAGs), affiliated into phylum-level bacterial and archaeal clades without cultivated representatives, contained genes involved in nitrogen metabolism including nitrification and denitrification. Our results show genetic components and their potential interactions for the biogeochemical nitrogen cycle in a subsurface geothermal environment.

著者

Satoko Noda Daichi Shimizu Masahiro Yuki Osamu Kitade Moriya Ohkuma

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17096, (Released:2018-01-24)

被引用文献数

44

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Cellulolytic flagellated protists inhabit the hindgut of termites. They are unique and essential to termites and related wood-feeding cockroaches, enabling host feeding on cellulosic matter. Protists of two genera in the family Teranymphidae (phylum Parabasalia), Eucomonympha and Teranympha, are phylogenetically closely related and harbor intracellular endosymbiotic bacteria from the genus Treponema. In order to obtain a clearer understanding of the evolutionary history of this triplex symbiotic relationship, the molecular phylogenies of the three symbiotic partners, the Teranymphidae protists, their Treponema endosymbionts, and their host termites, were inferred and compared. Strong congruence was observed in the tree topologies of all interacting partners, implying their cospeciating relationships. In contrast, the coevolutionary relationship between the Eucomonympha protists and their endosymbionts was more complex, and evidence of incongruence against cospeciating relationships suggested frequent host switches of the endosymbionts, possibly because multiple Eucomonympha species are present in the same gut community. Similarities in the 16S rRNA and gyrB gene sequences of the endosymbionts were higher among Teranympha spp. (>99.25% and >97.2%, respectively), whereas those between Teranympha and Eucomonympha were lower (<97.1% and <91.9%, respectively). In addition, the endosymbionts of Teranympha spp. formed a phylogenetic clade distinct from those of Eucomonympha spp. Therefore, the endosymbiont species of Teranympha spp., designated here as “Candidatus Treponema teratonymphae”, needs to be classified as a species distinct from the endosymbiont species of Eucomonympha spp.

著者

Tomohiro Inaba Tomoyuki Hori Yuya Sato Tomo Aoyagi Dai Hanajima Atsushi Ogata Hiroshi Habe

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17112, (Released:2017-12-12)

被引用文献数

13

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Limited information is currently available on the contribution of eukaryotes to the reactor performance of membrane bioreactors (MBRs). Using high-throughput Illumina sequencing of 18S rRNA genes and microscopic observations, we investigated eukaryotic microbiomes in membrane-attached biofilms in MBRs treating piggery wastewater. Protozoa preying on bacteria were frequently detected under stable conditions when membrane clogging was suppressed. However, the eukaryotes preying upon protozoa became predominant in biofilms when membrane fouling rapidly progressed. We herein demonstrated that a comprehensive investigation of eukaryotic microbiomes using high-throughput sequencing contributes to a better understanding of the microbial ecology involved in wastewater treatment.

著者

Ethan T. Hillman Hang Lu Tianming Yao Cindy H. Nakatsu

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17017, (Released:2017-11-10)

被引用文献数

366

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The ecosystem of the human gastrointestinal (GI) tract traverses a number of environmental, chemical, and physical conditions because it runs from the oral cavity to the anus. These differences in conditions along with food or other ingested substrates affect the composition and density of the microbiota as well as their functional roles by selecting those that are the most suitable for that environment. Previous studies have mostly focused on Bacteria, with the number of studies conducted on Archaea, Eukarya, and Viruses being limited despite their important roles in this ecosystem. Furthermore, due to the challenges associated with collecting samples directly from the inside of humans, many studies are still exploratory, with a primary focus on the composition of microbiomes. Thus, mechanistic studies to investigate functions are conducted using animal models. However, differences in physiology and microbiomes need to be clarified in order to aid in the translation of animal model findings into the context of humans. This review will highlight Bacteria, Archaea, Fungi, and Viruses, discuss differences along the GI tract of healthy humans, and perform comparisons with three common animal models: rats, mice, and pigs.

著者

Ruizhen Wang Leiming Dong Yuequ Chen Liangjian Qu Qinghua Wang Yongan Zhang

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME16167, (Released:2017-08-19)

被引用文献数

10

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Symbioses have played pivotal roles in biological, ecological, and evolutionary diversification. Symbiotic bacteria affect the biology of hosts in a number of ways. Esteya vermicola, an endoparasitic nematophagous fungus, has high infectivity in the pine wood nematode (PWN), which causes devastating ecological damage and economic losses in Asia and Europe. An integration of molecular, phylogenetic, and morphological analyses revealed that surface-sterilized E. vermicola with septate hyphae from different geographic locations harbor bacterial endosymbionts. 16S rRNA gene sequences from four fungal strains all clustered in a well-supported monophyletic clade that was the most closely related to Pseudomonas stutzeri and affiliated with Gammaproteobacteria. The existence and intracellular location of endobacteria was revealed by fluorescent in situ hybridization (FISH). Our results showed that endobacteria were coccoid, vertically inherited, as yet uncultured, and essential symbionts. Ultrastructural observations indicated that young and old endobacteria differed in cell size, cell wall thickness, and the degree of reproduction. The results of the present study provide a fundamental understanding of the endobacteria inside E. vermicola and raise questions regarding the impact of endobacteria on the biology, ecology, and evolution of their fungal host.

著者

Iulia Lupan Rahela Carpa Andreea Oltean Beatrice Simona Kelemen Octavian Popescu

出版者

日本微生物生態学会・日本土壌微生物学会

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

pp.ME17016, (Released:2017-08-05)

被引用文献数

30

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The occurrence and spread of bacterial antibiotic resistance are subjects of great interest, and the role of wastewater treatment plants has been attracting particular interest. These stations are a reservoir of bacteria, have a large range of organic and inorganic substances, and the amount of bacteria released into the environment is very high. The main purpose of the present study was to assess the removal degree of bacteria with resistance to antibiotics and identify the contribution of a wastewater treatment plant to the microbiota of Someşul Mic river water in Cluj county. The resistance to sulfamethoxazole and tetracycline and some of their representative resistance genes: sul1, tet(O), and tet(W) were assessed in this study. The results obtained showed that bacteria resistant to sulphonamides were more abundant than those resistant to tetracycline. The concentration of bacteria with antibiotic resistance changed after the treatment, namely, bacteria resistant to sulfamethoxazole. The removal of all bacteria and antibiotic-resistant bacteria was 98–99% and the degree of removal of bacteria resistant to tetracycline was higher than the bacteria resistant to sulfamethoxazole compared to total bacteria. The wastewater treatment plant not only contributed to elevating ARG concentrations, it also enhanced the possibility of horizontal gene transfer (HGT) by increasing the abundance of the intI1 gene. Even though the treatment process reduced the concentration of bacteria by two orders of magnitude, the wastewater treatment plant in Cluj-Napoca contributed to an increase in antibiotic-resistant bacteria concentrations up to 10 km downstream of its discharge in Someşul Mic river.